Improvement in grinding and pulverizing mills



J. T. DAVIS. Grinding and Pulverizing Mill. No. 212,664.

Patented Feb. 25,1879.

Unrrnn STATES PATE-Nr OFFICE.

JOHN T. DAVIS, OF SAN FRANCISCO, CALIFORNIA.

IMPROVEMENT IN GRINDING AND PULVERIZING MILLS.

Specilication forming part of Letters Patent No. 212,664, dated February 25, 1879 5 application led- November 22, 187B.

.To all whom it. may concern:

Be it known that I, JOHN T. DAVIS, of the 'city and county of San Francisco, and State "of California, have invented a Orushing and 'Grinding 4Mill 5 and I hereby declare the fol- 'lowing to be a full, clear, and exact descriprtion thereof, reference being had to the accompanying drawings.

My invention relates to an improved mechanism for pulverizing quartz, rock, grain, or other hard substances; and myimprovements refer more particularly to an apparatus of similar character for which. I have applied for Letters Patent.

My improvements in this instance consist in inclosing within the ease or cylinder three or more sets of dies, againstwhich the material to be crushed is thrown by the corresponding number of sets of shoes on the disk rotating in said cylinder until it is crushed to the required degree of iineness.

It further consists in regulating the discharge openings between the dies, so that while large openings are possible where the bulk of the ore is crushed at the center of the device the openings are smaller at the outer Circle of dies, so that the material is discharged of more uniform size than was possible in my previous invention.

It also consists in the details of construction, which are more fully described in the accompanying drawings, in which- Figure l is a view of my device with onehalt' of the side removed. Fig. 2 is a transverse section. Figs. 3 and 4 are details of construction. Y

A A are the sides of the case, to which lugs are attached for mounting the cylinder or case on the frame, as shown. Through the center of the sides is an open space, through which passes the shaft C, on which the centrally-revolving disk X is secured. On each side of this diskis mounted three or more sets of shoes,

secured to the disk by means of bolts or screws, handholes I) being provided in the sides of the case for their removal, as shown, and for keeping the machine cool. These shoes are set at suitable distances apart, and are set in three or more circles on the disk, according to the number of sets of dies which are used. The bolts holding them in position may be removed by means of the hand-holes, so that the shoes may be removed or changed whenever necessary.

Offsets E are formed in the sides of the case,

so that the shoes pass close to said oi'fsetsin their revolutions, in order to more effectually force the ore against the dies, as hereinafter described.

The dies F are made in short sections, for convenience of replacement, and in order that spaces a may be left between them for the purextensions, combined with the disk, divide the case or cylinder into two longitudinal compart ments, so that the material being crushed cannot passl from one compartment to the other until it is fine enough to pass through the small space left `between-the edge of the disk and the extensions. I do not, however, claim these extensions, broadly, as they are shown and described in a previous application of my own.

The dies are beveled off from one edge to the other, so as to tit in the circle in which they are placed, and also in order that that portion subject to the greatest wear shall be thicker than the remainder. The inner surfaces of these dies are corrugated, so that a greater crushin geffectis possible. These outera circle dies F have iianges Gr on each side, which rest on the offset formed on the sides of the case, and that part of the flanges projecting above bears againstthe rim or cover of the cylinder joining the sides together, and thus keeps the dies in position.

The dies which are used for the sets nearer the center of the cylinder are secured in the casein a diii'erent manner from those on the outer circle.

Flanges m are formed in one side, which it in the space p left between the offsets, and bolts or screws passing through the sides of the case enter the flanges'. and hold the dies in posi-tion. .Ehe flanges V on the other sides of said dies come close up to the disk, and project downward from the dies t0 prevent the particles of ore from passing from one circular compartment to the other.

The discharge from the circular compartments is accomplished by the particles passing through the spaces a left between the dies. At the circle nearest the center these spaces are comparatively large, and at the next cir cle smaller, and at the outer circle smaller still. By this means the ore is finally discharged more uniform in size than where it passes through discharge-openings which are all the same size.

By having three or more sets of shoes and dies in the same cylinder, instead of only one, as heretofore, the crushing capacity of the machine is very greatly enlarged with no appreciable increase of expenditure of power. The crushing-surface is greatly increased, as there are substantially three machines in one.

The ore is fed into the case through the openin gH at the center of the side ofthe case, where the rst set of beaters breaks it up tine enough to pass through the spaces between the dies,

when the next set of beaters and dies reduces the cover of the case and the outsideof the diesto the discharge-opening at the bottom-of the cylinder.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. The centrally-located rotating disk X', with its concentric series of shoes, in combination withthe concentric dies yF F within the case A, said dies having the discharge-openings a graduated and regulated, substantially as and for the purpose herein described.

2. The dies F, made in sections, and provid ed with the beveled extensions b, said extensions overlapping to form a continuous projecting ange or rim in the same plane with the disk, substantially as herein described.

3. The rotating disk X', with its shoes, as

shown, andthe dies F, with their dischargeopenings a, fitted within the case A, graduated and regulated as described, said case being provided with openings D', to admit air to keep the machine cool 'and assist in the discharge of material, substantially as hereindescribed. In witness whereof I have hereunto set my hand. JNO. T. DAVIS. Witnesses:

(JI-uis. G. YALE, FRA-NK A. BRooKs. 

